Modified Interim Mandibular Advancement (MIMA) Appliance for Symptomatic Correction of Obstructive Sleep Apnea

Obstructive Sleep Apnea (OSA) is a chronic, progressive, multifactorial, life-threatening disorder that causes significant impact on patient's life. Patients with OSA [Apnea/Hypopnea Index (AHI)>30] who cannot tolerate Continuous Positive Airway Pressure (CPAP) therapy or are not surgical candidates may benefit from oral appliances. This paper describes interim appliance devised from existing Hawley's retainer in patients with OSA. A 38-year-old man of athletic built with history of orthodontic treatment six months back due to esthetic concerns and wearing upper Hawley's retainer, reported with chief complaint of frequent nocturnal awakening along with excessive daytime somnolence. Based on diagnostic aids, he was diagnosed with Class II Division 1 malocclusion with severe mandibular retrusion. Sleep test revealed AHI score of 34, suggestive of severe OSA. With ENT and Oral surgeon concurrence, mandibular advancement of 7mm with Bilateral Sagital Split Osteotomy (BSSO) with distraction was contemplated as a viable functional and curative stable treatment plan. Because of non-adherence and non-compliance with CPAP therapy and on request of patient, an interim anterior positioning appliance was devised to facilitate comfortable sound sleep till the time surgery is impending. After three months of wearing this customized appliance, improved quality of sleep was discernible; both subjectively as reported by patient and objectively using sleep test (AHI=9.8).